1. Field of the Disclosure
The present disclosure relates generally to electrophotographic printers and more particularly to a sealing member having internal lubricant additives for use in an electrophotographic printer.
2. Description of the Related Art
Various seals are used in electrophotographic printers to prevent toner from leaking between the printer's components. For example, toner leakage may occur from the gaps between a developer roll that supplies toner to a photoconductive drum of the electrophotographic printer, a doctor blade in contact with the developer roll and the housing of a replaceable unit that holds the developer roll and the doctor blade. Seals may be provided to effectively close the gaps between these components to prevent toner leakage. For example, a J-shaped seal may be used at each axial end of the developer roll to prevent toner from leaking out of the junction between the developer roll, the doctor blade and the housing of the replaceable unit. The J-shaped seals may comprise a molded (e.g., injection molded or compression molded) part made of a polymeric based elastomeric material.
The J-shaped seal may also include a lubricant additive internal to its composition that reduces the friction between the seal and the developer roll. For example, prior seals included in the elastomeric material about 1% silicone oil and about 1% polytetrafluoroethylene (TEFLON® available from E.I. du Pont de Nemours and Company (DuPont™)) by weight of the seal. However, as print speeds increase (e.g., greater than 40 pages per minute), the friction between the J-shaped seal and the developer roll increases. In some cases, the increased friction may increase the wear on the seal reducing the seal's useful life. Further, the increased friction may generate heat sufficient to prematurely melt the toner resulting in print defects and toner leakage. As print speeds increase and longer life components are desired, an internal lubricant that reduces frictional heating, prevents thermal failures and extends the life of the seal at higher print speeds is desired. Some prior seals also included an externally applied silicone wax but this external lubricant gradually wears away over the life of the seal. Attempts to reduce frictional heating by reducing the force between the J-shaped seals and the developer roll by using softer materials or dimensional changes have failed because the lower force is insufficient to seal the toner.